Sets

// create a set
var mySet: Set = ["one", "two", "three", "four"]
// iterate over all items in the set
for item in mySet {
print(item)
}

Just as a reminder: a Set is more or less the same as an Array, with the exception that this collection has no order. Whilst iterating over an Array will always show the first item first, the order of a Set is unpredictable. Fetching a Set is slightly faster than an Array.